Given the task definition and input, reply with output. In this task, you will be presented with a context from an academic paper and a question separated with a 
. You have to answer the question based on the context.

We represent each instance of image, question, and user choice as a triplet consisting of image feature, question feature, and the label vector for the user's answer. In addition, collecting multiple choices from identical users enables us to represent any two instances by the same user as a pair of triplets, assuming source-target relation. With these pairs of triplets, we can train the system to predict a user's choice on a new image and a new question, given the same user's choice on the previous image and its associated question. As discussed earlier, we attempt to reflect user's interest by asking questions that provide visual context. In other words, a question whose answer is so obvious that it can be answered in an identical way would not be valid as an interactive question.   If the most likely candidate $c_i=\max p_{ans}$ , where $c_i \in C$ , has a probability of being answer over a certain threshold $\alpha $ , then the question is considered to have a single obvious answer, and is thus considered ineligible.  In our experiments, we set $\alpha $ as 0.33. We also excluded the yes/no type of questions.  
 Question: What are the features of used to customize target user interaction? 

image feature question feature label vector for the user's answer